Your school notebooks are probably filled with all sorts of doodles. If you want to be a serious journalist, though, you need to learn to take notes without drawing Adventure Time characters in the margins…assuming you take actual notes with an actual pen on actual paper, of course.
In the 70's, pen and paper was the only option for taking notes. But as Woodward and Bernstein show us, paper can take the form of napkins, the backs of receipts, or coasters. Basically any flat surface that was shaved off a tree is fair game. The men had to keep track of every piece of paperwork and every note they took to verify their stories. The most memorable scene involving note paper (that's a phrase you don't hear every day) shows Bernstein dumping out scraps from his pockets after scrambling to write notes on everything Sloan's bookkeeper says.
Paper's also important off-screen. The reporters have to investigate the shredding of important documents at the CREEP office. To today's paperless society this might seem archaic, but that was the way it was done back in the dark, paper-saturated ages of the 1970's.